Narrative:The Dutch airline KLM expressed an interest in the Model B-307. KLM test pilot Albert von Baumhauer and another engineer traveled to Seattle for an evaluation. Von Baumhauer wanted to test the Stratoliner at low speed with engines on one side shut down. Despite the low likelihood of such a combination of conditions, Chief Aerodynamicist Ralph Cram agreed to the test, with number NX19901 prototype.According to the findings of the accident investigation, the aircraft was at 10,000 feet when the maneuver was attempted. The airplane stalled and went into a spin. This failure was traced to ailerons and a tail fin too small for this design (plans to modify the original bomber flight surfaces had already been finalized, but had not been incorporated into the prototype NX 19901).Boeing test pilot Julius Barr and von Baumhauer attempted to recover from the spin, but their struggle against the control column resulted in the wings and tail section separating from the fuselage. Also killed in the crash was Boeing Chief Engineer Earl Ferguson, a representative from TWA, and five other Boeing employees.

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Map

This map shows the airport of departure and the intended destination of the flight. The line between the airports does not display the exact flight path. Distance from Seattle-Boeing Field International Airport, WA to Seattle-Boeing Field International Airport, WA as the crow flies is 0 km (0 miles).

This information is not presented as the Flight Safety Foundation or the Aviation Safety Networkĺs opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.